Dreoging-machine



` 'No Model.)

N0.502,934. Patented Aug.8,189s.

UNITED STATES PATENT OF-FICE. l

WILLIAMB. PLEss, or SANZ FRANCISCO, CALIFORNIA, AssiGN'oR T o THEPLEss-DREDGING AND RECLAMATICN-CoMPANY,"oF NEVADA."

DR-EDGING-MAoH-INE., f

SPECIFICATION forming-part of Letters Patent No. 502,934, dated Agust s,189s. Application led September. 21', 1892. Serial Ne. 446,391. (Nomodel.)

T01` aZZ whom it may concern/.-

Beit known that I, WILLIAM B. PLEss, a citizen of the United States,residing at San Francisco, in the county of lSan Francisco and State ofOaliforn-ia,have invented certain new and useful Improvements inDredging-Mae chines; and I do hereby'declare that the following is afull,- clear, and exact description thereof.

Thisinventi'on relates to dredgingmachines, and more especially to thatclass ofdredgers in which a bucket composed of two sections hingedtogether,'is suspendedfrom'a swing' ,ing boom or derrick, and connectedto suitablehoisting mechanismfcarried by afloating hull or scow.

In Letters Patent N o. 426,681, granted to me April 29, 1890, Idescribed and showed a dredging apparatus of the type above referred to;and my. present invention consists in certain improvement-s upon'theconstruction of the bucket shown in that patent and upon the means forhoisting, lowering, opening, and closing the hinged sections or jaws ofthe bucket. The mechanism for supporting the boolnand for swinging ittordischarge the bucket are preferably like that shown'in the said patent,but form an essential part of the ypresent invention which will befullyunderstood byfreference tothe following detailed description, and to theaccompanying draw@ ings in'whichd Flgure 1, is a side elevation of thewhole dredging apparatus. Fig. 2, is an elevation of the bucket with thejaws opened. j Fig.` 3,1

is a detail view lof the lend of the boomv showing the cap 'and sheavesfor the passage of the hoisting chains. f Fig. 4, is an end eleva tionwith the jaws closed. 1

Afrepresents the hull of the -dredger'hav-l ing a deck` house to containthe boilers, en

gine and winding machinery. B is a hollow rotary mast, stepped in thehull, and having secured near its lower end thefoot of the projectingboom '0. D is a turn-table secured to the mast, and connected to theboom by jaws 1, as in my former patent, or by chains if preferred. Theturn table is connected t; the winding machinery by a chain 2. All these5o parts are substantially as shown in my former patent, and are of theconstruction I prefer to use, but form no part of my present invention.They are all shown in the drawings however, in order to give a generalidea of the relative positions' and operations ofthe boomv 4mast andwinding mechanism. 'j'

The dredgebucketis illustrated-in detail in Figs. 2 and 4. It consists'of two sections E and, F,preferably of heavy boiler iron, each,

in side elevation being approximately lin the shape of avquadrantof acircle. To each end of each section is firmly bolted a heavy arm G, eachpair of vvsuch arms bein'g pivoted te-` In like manner i was connectedto each section. Each sheave' block was then suspended.` by anindependent chain fixed to the extreme end of the boom, then passing,first, around its appropriate block, then backto., a pulley on the boom,and thence to the mast and winding gear. devices/have'proved to beunnecessarily complica-ted and`l though Iobtained such a purchase' astogive a power much in excess of that required,the lhoisting movementswerev kextremely slow and the Working capacity-of the machine was notmore than fty percent.

of that `of -a dredge constructed according' to These v my present`invention. v There are other dis-1.

advantages of .the sheaveblock systemof suspension .which I-shallexplain in connection.

with the detailed description of my present imp rovements.- v

Referring to Figs. 2' and 4 it will be seen that four chains'H aresecured to the corners of the bucket sections .and extend to a simplering I upon which they can move freely.

From this ring a single suspension chain J passes over a sheave at theextremity of the boem and thence to the mast and windingv mechanism. Thechains K by which the movements .of the bucket sections are controlled,

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s y i 502,934

are secured to linksjL, each composed of two bars 4,. ',.securedtogether by pins 6, 7, to one lof which the'chain is connected and bythe Vseveral reasons the links are preferable.

other of which the linksare pivoted to the outwardly bent extensions Gon thearms G. The chains K are then connected to a rin n: L', from whichthe single suspension chain' Mextendsv over a sheave at the extremity ofthe boom and thence to the lmast and winding machinery. ItA-might bepossible toconnect shown: by Fig. 2, if the chains were attacheddirectly to the ends of thelevers they would interfere 4with the actionof the armsand bucket by chaiingand friction. By using'the links,the-chainswor'k entirely free-without obstruction. It will be observedthat the 'links are four in number, being duplicated on 4each side; armextensions.l .They are sustained laterally, during therststrain ofclosing the bucket. Whensofoldedgon the. arm the apparatus-is compactand the short cross chainskare heldV free from entanglement, byreasonoftheir connection with the ring.' As the buckets closreitheilinks` unfoldand extend the connectionsfbetween the arms and,r ring and thus`-relieve the lateral 4strain in hoisting.

It will be seen that by these improvements allsheav'e blocks and tackleof that charac pull from thehoistn g machinery to the bucket is direct.FurthermorethechansH are self ada listing in.the-supportingringso thatif by y' chance. oneside of the bucket should not enter the soil,thechains in oneside'will slacken 'and thusrelieve the strain whichwould probablyfensue if ade'vice which creates such frictionasasheaveblock were-nsedfor supporting the chains. As in this case `bothsupport-' ing,` chains pass over the boom at. its extremity, and at thatpoint only, Iam able to use the construction shown in Fig. 3, whichwould be impracticablewith the device shown in my former. patent. VInthatV patent I showed both hoisting; chains passing through a hole andover sheaves in the wooden. boom. My present improvement` consists in ahollow cap and sleeve mounted upon the extreme end of "theA boom,.whichis `formed into a bearing for, it. This cap whichisa single steel.casting con- When .down theyrclose uponthe tains the sheaves over whichlthe hoisting ropes pass; and beingloose on the end of the boom,although held in place by the weight of the bucket will remain in "placeand keep theV sheaves in line in case theboom itself should becometwisted from. any cause. The

lcast cap moreover prevents all the wear to which the wooden boomis'subjected by the old construction. C 'In operating the bucket, bothsuspension chains are wound up,"lifting'the"bucket -and at the same timeopening,r the section; 4both f chains are then slackened,loweringthebucket upon the bottom. The chain J is then wound lcausing thesections of the bucket to close and take the load which is thenelevated. The boom is then swung around to thefproper positition todischarge and the chainJ is slack-'- cned, whereby the weight of theload causes the bucket to open= and discharge itsload. lTheboom isthenswung back tothe dredg-` ing point and dropped upon'the bottom again,

r the same operation proceeding as long as may be necessary.

What I claim is- Y l. In combination withtheboom of adredge. l havingsheaves fondnplicate-chains, a dredge bucket composedof two sect-ionseach; having` anA army G with outwardly bent extensionsfG,

linksLpivoted to the outer ends of theseexy tensions, and connected at;their upperends Yby a ring -to-achain-M,.achain1.l connected by chains Ht'o the corners of therbucket sec tions, the chainsJ and Mbeingzarrangcd ontheyboomsheaves, all:4 substantially as de scribed. terare entirely done away with,and that the i 2.. Incombination withthebuck-et sections. an arm G fixed toeach. side-of each-V section,

`and havingan outwardly' bent extension, a jlinkl composedr of two barspivotedonxthe 'outer endlofeach extension and connectediat its upperendE by a' chain to aring, and a chain Y M, connected to said ringgallvsubstantially as described. l

3. In a dredgingmachine, aswinging boom;

IUD

in combination witha' loosesleeve and cap at In testimony whereof I`have axed `my sig nature, in presence ot'l two'witnessesythis 5th day ofSeptember, 1892.

' WILLIAM B. PLESS.`

Witnesses:

YL. W. SEELY,.

THOMASMULLIGAN.

